#include<iostream>

namespace shuaige
{
	int a = 9;
}

using shuaige::a;

void f()
{}

int f(int a = 10, int b = 20)
{
	return a;
}

int main()
{
	
	//float b = 2.5;
	//char c = 'x';

	////std::cin >> a >> b >> c;
	//std::cout <<  ' ' << shuaige::a << ' ' << b << ' ' << c << std::endl;

	int b = f();

	return 0;
}